As British pilots desperately fought off the German blitz during the Battle of Britain in 1940, a devastating flaw was discovered in the engines of the Royal Air Force’s iconic Hurricane fighter-bombers and Spitfire fighter planes — whenever the planes dived, their carburetors flooded with fuel, causing the engine to cut out. If it weren’t for Beatrice “Tilly” Shilling, a young engineering graduate of the University of Manchester who innovated the solution to the plane engine’s carburetor trouble, Britain might have lost WWII almost before it even begun.

Born in 1909 in Waterlooville, Hampshire, Shilling developed an obsession with engines almost as soon as she could walk.

“As a child I played with Meccano,” said Shilling in an interview with Woman Engineer magazine, referring to a toy model construction system designed to encourage children to engage in engineering. “I spent my pocket money on penknives, an adjustable spanner, a glue pot and other simple hand tools.”

In 1932, Shilling graduated from the Victoria University of Manchester as one of only two female engineering graduates that year. Shilling went on to complete a Master of Science, before pursuing a career in motorcycle racing where she became famous for outfitting her bike with a supercharger and reaching speeds of 106 mph. According to Dr. Christine Twigg of the University of Manchester, Shilling received the Brooklands gold star for her outstanding performances in track and road racing.

In 1936, Shilling began specializing in aircraft carburetors with the Royal Aircraft Establishment. And when RAF pilots began noticing a potentially fatal problem in their carburetors in 1940, it was Shilling who came up with the RAE restrictor — “a diaphragm to stop fuel surge.”

It was “a war-winning modification, without which we would have suffered … defeat,” explained Keith “Mad Dog” Maddock, the chief engineer at Hangar 42, a WWII era aircraft hangar which is now used to reconstruct Spitfires. “Beatrice Shilling helped us to win World War Two — of that there is no doubt.”

Shilling would be appointed an OBE in 1947 for her contribution to the war effort, and continued to work for the RAE until her retirement in 1969. Shilling, who died on November 18, 1990, at the age of 81, is featured in Invented in the North West, a special BBC One program now available for streaming on the BBC iPlayer.

Watch a video explaining Shilling’s innovation in further detail below.